1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
/* Copyright (C) 1994-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <hurd.h>
#include <hurd/fd.h>
#include <hurd/resource.h>
#include <stdlib.h>
#include "hurdmalloc.h" /* XXX */
/* Allocate a new file descriptor and return it, locked. The new
descriptor number will be no less than FIRST_FD. If the table is full,
set errno to EMFILE and return NULL. If FIRST_FD is negative or bigger
than the size of the table, set errno to EINVAL and return NULL. */
struct hurd_fd *
_hurd_alloc_fd (int *fd, int first_fd)
{
int i;
void *crit;
long int rlimit;
if (first_fd < 0)
{
errno = EINVAL;
return NULL;
}
crit = _hurd_critical_section_lock ();
__mutex_lock (&_hurd_dtable_lock);
search:
for (i = first_fd; i < _hurd_dtablesize; ++i)
{
struct hurd_fd *d = _hurd_dtable[i];
if (d == NULL)
{
/* Allocate a new descriptor structure for this slot,
initializing its port cells to nil. The test below will catch
and return this descriptor cell after locking it. */
d = _hurd_new_fd (MACH_PORT_NULL, MACH_PORT_NULL);
if (d == NULL)
{
__mutex_unlock (&_hurd_dtable_lock);
_hurd_critical_section_unlock (crit);
return NULL;
}
_hurd_dtable[i] = d;
}
__spin_lock (&d->port.lock);
if (d->port.port == MACH_PORT_NULL)
{
__mutex_unlock (&_hurd_dtable_lock);
_hurd_critical_section_unlock (crit);
if (fd != NULL)
*fd = i;
return d;
}
else
__spin_unlock (&d->port.lock);
}
__mutex_lock (&_hurd_rlimit_lock);
rlimit = _hurd_rlimits[RLIMIT_OFILE].rlim_cur;
__mutex_unlock (&_hurd_rlimit_lock);
if (first_fd < rlimit)
{
/* The descriptor table is full. Check if we have reached the
resource limit, or only the allocated size. */
if (_hurd_dtablesize < rlimit)
{
/* Enlarge the table. */
int save = errno;
struct hurd_fd **new;
/* Try to double the table size, but don't exceed the limit,
and make sure it exceeds FIRST_FD. */
int size = _hurd_dtablesize * 2;
if (size > rlimit)
size = rlimit;
else if (size <= first_fd)
size = first_fd + 1;
if (size * sizeof (*_hurd_dtable) < size)
{
/* Integer overflow! */
errno = ENOMEM;
goto out;
}
/* If we fail to allocate that, decrement the desired size
until we succeed in allocating it. */
do
new = realloc (_hurd_dtable, size * sizeof (*_hurd_dtable));
while (new == NULL && size-- > first_fd);
if (new != NULL)
{
/* We managed to allocate a new table. Now install it. */
errno = save;
if (first_fd < _hurd_dtablesize)
first_fd = _hurd_dtablesize;
/* Initialize the new slots. */
for (i = _hurd_dtablesize; i < size; ++i)
new[i] = NULL;
_hurd_dtablesize = size;
_hurd_dtable = new;
/* Go back to the loop to initialize the first new slot. */
goto search;
}
else
errno = ENOMEM;
}
else
errno = EMFILE;
}
else
errno = EINVAL; /* Bogus FIRST_FD value. */
out:
__mutex_unlock (&_hurd_dtable_lock);
_hurd_critical_section_unlock (crit);
return NULL;
}
|
